EBV-associated epithelial cancers cells promote vasculogenic mimicry formation via a secretory cross-talk with the immune microenvironment.

Background: Vasculogenic mimicry (VM) induced by Epstein-Barr virus (EBV) infection plays an important role in resistance to anti-vascular endothelial growth factor (VEGF) therapy in EBV-associated epithelial cancers; however, the interaction between VM and the immune microenvironment has not been systematically investigated. Methods: IHC and multiplex IHC analysis the relationships among tumour-associated macrophage (TAM), VM and EBV infection in EBV-associated epithelial cancer biopsies. In vitro and in vivo evidence using CRISPR-Cas9 system engineered EBV-infected epithelial cancer cells and mouse models support functional role and mechanism for M2c-like macrophages in the VM formation. The prediction of VM in the effectiveness of anti-angiogenic agent was analysed using clinical datasets. Results: EBV-associated epithelial cancer biopsies revealed that infiltration of the TAM surrounding the VM is closely associated with EBV infection. AKT/mTOR/HIF-1α pathway in EBV-infected epithelial cancer cells control the secretion of CCL5 and CSF-1, enabling the recruitment of monocytes and their differentiation into M2c macrophages which promote VM formation by MMP9. Combination of anti-angiogenesis agents and HIF-1α inhibitor caused marked decreases in CD31-positive micro-vessels, VM, and M2c-like macrophages. VM scores can be used as biomarkers to predict the efficacy of anti-angiogenic agent therapy in EBV-associated epithelial cancers. Conclusions: Our findings define a secretory cross-talk between tumour cells and the immune microenvironment in EBV-associated epithelial cancer, revealing an unexpected role of EBV in epithelial cancer cells, controlling VM formation via M2c-like macrophages.

FGFR4-specific CAR-T cells with inducible caspase-9 suicide gene as an approach to treat rhabdomyosarcoma.

Metastatic rhabdomyosarcoma is associated with poor survival and unsatisfactory treatment outcomes. Therefore, new immunotherapeutic methods are urgently required. Fibroblast growth factor receptor 4 (FGFR4), a new therapeutic target for rhabdomyosarcoma, plays a crucial role in its onset and development. This study aimed to generate FGFR4 single-chain variable fragment-based chimeric antigen receptor (CAR) T cells without causing evident toxicity and incorporating an inducible caspase-9 (iCasp9) suicide gene system to enhance their safety. FGFR4 antigen expression was evaluated in normal murine tissues, normal human tissues, and specimens from patients with rhabdomyosarcoma. Combined with a 4-1BB co-stimulatory domain, a CD3ζ signaling domain, and an iCasp9 suicide gene, CAR-T cells with an FGFR4-specific single-chain variable fragment were developed. The specific cytotoxic effects, T-cell proliferation, cytokine secretion, apoptosis induction by chemical dimerization (AP20187), and toxicity of FGFR4 CAR-T cells were investigated in vitro and in vivo. FGFR4 CAR-T cells generated a variety of immune-promoting cytokines, including tumor necrosis factor α, interleukin 2, and interferon γ, and displayed effective cytotoxic activity against FGFR4-overexpressing rhabdomyosarcoma cells in vitro. FGFR4 CAR-T cells were relatively effective against FGFR4-overexpressing rhabdomyosarcoma, with tumor regression and poor survival in a subcutaneous xenograft model. The iCasp9 gene was incorporated into FGFR4 CAR-T cells and it was demonstrated that effective and reliable suicide gene activity depends on the administration of AP20187. By making use of the cross-reaction of FGFR4 CAR-T cells with murine FGFR4 in a syngeneic tumor model, this study found that FGFR4 CAR-T cells could regulate the growth of tumors without evident toxicity. Our study demonstrates that FGFR4 is a prospective target for CAR-T cell therapy in rhabdomyosarcoma without serious on-target off-tumor toxicity. FGFR4 CAR-T cells with the iCasp9 suicide gene system as a safety switch to limit toxicity may broaden the clinical applications of cellular therapy.

EBV promotes TCR-T-cell therapy resistance by inducing CD163+M2 macrophage polarization and MMP9 secretion.

BACKGROUND: Epstein-Barr virus (EBV) is a double-stranded DNA oncogenic virus. Several types of solid tumors, such as nasopharyngeal carcinoma, EBV-associated gastric carcinoma, and lymphoepithelioma-like carcinoma of the lung, have been linked to EBV infection. Currently, several TCR-T-cell therapies for EBV-associated tumors are in clinical trials, but due to the suppressive immune microenvironment of solid tumors, the clinical application of TCR-T-cell therapy for EBV-associated solid tumors is limited. Figuring out the mechanism by which EBV participates in the formation of the tumor immunosuppressive microenvironment will help T cells or TCR-T cells break through the limitation and exert stronger antitumor potential. METHODS: Flow cytometry was used for analyzing macrophage differentiation phenotypes induced by EBV-infected and EBV-uninfected tumors, as well as the function of T cells co-cultured with these macrophages. Xenograft model in mice was used to explore the effects of M2 macrophages, TCR-T cells, and matrix metalloprotein 9 (MMP9) inhibitors on the growth of EBV-infected tumors. RESULTS: EBV-positive tumors exhibited an exhaustion profile of T cells, despite the presence of a large T-cell infiltration. EBV-infected tumors recruited a large number of mononuclear macrophages with CCL5 and induced CD163+M2 macrophages polarization through the secretion of CSF1 and the promotion of autocrine IL10 production by mononuclear macrophages. Massive secretion of MMP9 by this group of CD163+M2 macrophages induced by EBV infection was an important factor contributing to T-cell exhaustion and TCR-T-cell therapy resistance in EBV-positive tumors, and the use of MMP9 inhibitors improved the function of T cells cocultured with M2 macrophages. Finally, the combination of an MMP9 inhibitor with TCR-T cells targeting EBV-positive tumors significantly inhibited the growth of xenografts in mice. CONCLUSIONS: MMP9 inhibitors improve TCR-T cell function suppressed by EBV-induced M2 macrophages. TCR-T-cell therapy combined with MMP9 inhibitors was an effective therapeutic strategy for EBV-positive solid tumors.

Epstein-Barr virus causes vascular abnormalities in epithelial malignancies through upregulating ANXA3-HIF-1α-VEGF pathway.

Angiogenesis is one of the characteristics of malignant tumors, and persistent generation of abnormal tumor blood vessels is an important factor contributing to tumor treatment resistance. Epstein-Barr virus (EBV) is a highly prevalent DNA oncogenic virus that is associated with the development of various epithelial malignancies. However, the relationship between EBV infection and tumor vascular abnormalities as well as its underlying mechanisms is still unclear. In this study, we found that compared to EBV-uninfected tumors, EBV-infected tumors were more angiogenic, but the neovascularization was mostly immature vessels without pericyte attachment in both clinical patient tumor samples and mouse xenograft models; These immature vessels exhibited aberrant functionality, characterized by poor blood perfusion and increased vascular permeability. The vascular abnormalities caused by EBV infection exacerbated tumor hypoxia and was responsible for accelerated tumor growth. Mechanistically, EBV infection upregulated ANXA3-HIF-1α-VEGF pathway. Silencing the ANXA3 gene or neutralizing ANXA3 with an antibody can diminish vascular abnormalities, thereby increasing immune cell infiltration and alleviating treatment resistance. Finally, a new therapy combining ANXA3 blockade and NK cell + PD1 antibody significantly inhibited the growth of EBV-infected xenografts in mice. In conclusion, our study identified a previously unrecognized role for EBV infection in tumor vascular abnormalities and revealed its underlying mechanism that upregulated the ANXA3-HIF-1α-VEGF pathway. ANXA3 is a potential therapeutic target for EBV-infected tumors and ANXA3 blockade to improve vascular conditions, in combination with NK cell + PD1 antibody therapy, holds promise as an effective treatment strategy for EBV-associated epithelial malignancies.

SMG5 Inhibition Restrains Hepatocellular Carcinoma Growth and Enhances Sorafenib Sensitivity.

Hepatocellular carcinoma (HCC) has a pathogenesis that remains elusive with restricted therapeutic strategies and efficacy. This study aimed to investigate the role of SMG5, a crucial component in nonsense-mediated mRNA decay (NMD) that degrades mRNA containing a premature termination codon, in HCC pathogenesis and therapeutic resistance. We demonstrated an elevated expression of SMG5 in HCC and scrutinized its potential as a therapeutic target. Our findings revealed that SMG5 knockdown not only inhibited the migration, invasion, and proliferation of HCC cells but also influenced sorafenib resistance. Differential gene expression analysis between the control and SMG5 knockdown groups showed an upregulation of methionine adenosyltransferase 1A in the latter. High expression of methionine adenosyltransferase 1A, a catalyst for S-adenosylmethionine (SAM) production, as suggested by The Cancer Genome Atlas data, was indicative of a better prognosis for HCC. Further, an ELISA showed a higher concentration of SAM in SMG5 knockdown cell supernatants. Furthermore, we found that exogenous SAM supplementation enhanced the sensitivity of HCC cells to sorafenib alongside changes in the expression of Bax and Bcl-2, apoptosis-related proteins. Our findings underscore the important role of SMG5 in HCC development and its involvement in sorafenib resistance, highlighting it as a potential target for HCC treatment.

XELOX (capecitabine plus oxaliplatin) plus bevacizumab (anti-VEGF-A antibody) with or without adoptive cell immunotherapy in the treatment of patients with previously untreated metastatic colorectal cancer: a multicenter, open-label, randomized, controlled, phase 3 trial.

Fluoropyrimidine-based combination chemotherapy plus targeted therapy is the standard initial treatment for unresectable metastatic colorectal cancer (mCRC), but the prognosis remains poor. This phase 3 trial (ClinicalTrials.gov: NCT03950154) assessed the efficacy and adverse events (AEs) of the combination of PD-1 blockade-activated DC-CIK (PD1-T) cells with XELOX plus bevacizumab as a first-line therapy in patients with mCRC. A total of 202 participants were enrolled and randomly assigned in a 1:1 ratio to receive either first-line XELOX plus bevacizumab (the control group, n = 102) or the same regimen plus autologous PD1-T cell immunotherapy (the immunotherapy group, n = 100) every 21 days for up to 6 cycles, followed by maintenance treatment with capecitabine and bevacizumab. The main endpoint of the trial was progression-free survival (PFS). The median follow-up was 19.5 months. Median PFS was 14.8 months (95% CI, 11.6-18.0) for the immunotherapy group compared with 9.9 months (8.0-11.8) for the control group (hazard ratio [HR], 0.60 [95% CI, 0.40-0.88]; p = 0.009). Median overall survival (OS) was not reached for the immunotherapy group and 25.6 months (95% CI, 18.3-32.8) for the control group (HR, 0.57 [95% CI, 0.33-0.98]; p = 0.043). Grade 3 or higher AEs occurred in 20.0% of patients in the immunotherapy group and 23.5% in the control groups, with no toxicity-associated deaths reported. The addition of PD1-T cells to first-line XELOX plus bevacizumab demonstrates significant clinical improvement of PFS and OS with well tolerability in patients with previously untreated mCRC.

N6-methyladenosine-modified VGLL1 promotes ovarian cancer metastasis through high-mobility group AT-hook 1/Wnt/ß-catenin signaling.

The main causes of death in patients with ovarian cancer (OC) are invasive lesions and the spread of metastasis. The present study aimed to explore the mechanisms that might promote OC metastasis. Here, we identified that VGLL1 expression was remarkably increased in metastatic OC samples. The role of VGLL1 in OC metastasis and tumor growth was examined by cell function assays and mouse models. Mechanistically level, METTL3-mediated N6-methyladenosine (m6A) modification contributed to VGLL1 upregulation in an IGF2BP2 recognition-dependent manner. Furthermore, VGLL1 directly interacts with TEAD4 and co-transcriptionally activates HMGA1. HMGA1 further activates Wnt/ß-catenin signaling to enhance OC metastasis by promoting the epithelial-mesenchyme transition traits. Rescue assays indicated that the upregulation of HMGA1 was essential for VGLL1-induced metastasis. Collectively, these findings showed that the m6A-induced VGLL1/HMGA1/ß-catenin axis might play a vital role in OC metastasis and tumor growth. VGLL1 might serve as a prognostic marker and therapeutic target against the metastasis of OC.

Anlotinib as a maintenance treatment for advanced soft tissue sarcoma after first-line chemotherapy (ALTER-S006): a multicentre, open-label, single-arm, phase 2 trial.

Background: No standard maintenance treatment has been obtained to prolong the response duration of soft tissue sarcoma (STS) after first-line chemotherapy. In this study, we aimed to evaluate the efficacy and safety of anlotinib as a maintenance treatment after chemotherapy in STS. Methods: In this multicentre, open-label, single-arm phase 2 trial, patients with advanced STS who achieved partial response or stable disease after first-line anthracycline-based chemotherapy were enrolled between April 2019 and January 2022. All patients received anlotinib as a maintenance treatment. The primary endpoint was progression-free survival (PFS) of anlotinib maintenance treatment. Other endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR) and safety. This study is registered with ClinicalTrials.gov, NCT03890068. Findings: At the data cut-off date (August 8, 2022), 49 patients were enrolled, including 17 with liposarcoma (35%) and 15 with leiomyosarcoma (31%). After a median follow-up of 17.1 months (IQR 9.0-27.2), the median PFS from the beginning of maintenance treatment was 9.1 months (95% CI 5.7-12.5), and the median OS was not reached, and the 1-year OS rate for anlotinib maintenance treatment was 98.0%. The best ORR and DCR were 16% (8/49, 95% CI 7-30) and 94% (46/49, 95% CI 83-99), respectively. Most of the treatment-related adverse events were grade 1-2. Of the grade 3-4 adverse events, the most common were hypertension (10%) and hand-foot syndrome reaction (6%). Interpretation: Postchemotherapy maintenance treatment with anlotinib exhibits promising efficacy and tolerable toxicity in patients with advanced STS. Funding: Chia Tai Tianqing Pharmaceutical Group Co., Ltd., the National Key Research and Development Program of China, and the National Natural Science Foundation of China.

Lenvatinib improves anti-PD-1 therapeutic efficacy by promoting vascular normalization via the NRP-1-PDGFRß complex in hepatocellular carcinoma.

Introduction: The limited response to immune checkpoint blockades (ICBs) in patients with hepatocellular carcinoma (HCC) highlights the urgent need for broadening the scope of current immunotherapy approaches. Lenvatinib has been shown a potential synergistic effect with ICBs. This study investigated the optimal method for combining these two therapeutic agents and the underlying mechanisms. Methods: The effect of lenvatinib at three different doses on promoting tissue perfusion and vascular normalization was evaluated in both immunodeficient and immunocompetent mouse models. The underlying mechanisms were investigated by analyzing the vascular morphology of endothelial cells and pericytes. The enhanced immune infiltration of optimal-dose lenvatinib and its synergistic effect of lenvatinib and anti-PD-1 antibody was further evaluated by flow cytometry and immunofluorescence imaging. Results: There was an optimal dose that superiorly normalized tumor vasculature and increased immune cell infiltration in both immunodeficient and immunocompetent mouse models. An adequate concentration of lenvatinib strengthened the integrity of human umbilical vein endothelial cells by inducing the formation of the NRP-1-PDGFRß complex and activating the Crkl-C3G-Rap1 signaling pathway in endothelial cells. Additionally, it promoted the interaction between endothelial cells and pericytes by inducing tyrosine-phosphorylation in pericytes. Furthermore, the combination of an optimal dose of lenvatinib and an anti-PD-1 antibody robustly suppressed tumor growth. Conclusions: Our study proposes a mechanism that explains how the optimal dose of lenvatinib induces vascular normalization and confirms its enhanced synergistic effect with ICBs.

Phase 1 clinical trial to assess safety and efficacy of NY-ESO-1-specific TCR T cells in HLA-A∗02:01 patients with advanced soft tissue sarcoma.

New York esophageal squamous cell carcinoma-1 (NY-ESO-1)-specific T cell receptor (TCR) T cell therapy is effective in tumors with NY-ESO-1 expression, but a safe and effective TCR-T cell therapeutic protocol remains to be improved. Here, we report a phase 1 investigational new drug clinical trial with TCR affinity-enhanced specific T cell therapy (TAEST16001) for targeting NY-ESO-1. Enrolled patients receive TAEST16001 cell infusion after dose-reduced lymphodepletion with cyclophosphamide (15 mg/kg/day × 3 days) combined with fludarabine (20 mg/m2/day × 3 days), and the TCR-T cells are maintained with low doses of interleukin-2 injection post-adoptive transfer. Analysis of 12 patients treated with the regimen demonstrates no treatment-related serious adverse events. The overall response rate is 41.7%. The median progression-free survival is 7.2 months, and the median duration of response is 13.1 months. The protocol of TAEST16001 cells delivers a safe and highly effective treatment for patients with advanced soft tissue sarcoma (ClinicalTrials.gov: NCT04318964).

Targeted delivery of a PD-1-blocking scFv by CD133-specific CAR-T cells using nonviral Sleeping Beauty transposition shows enhanced antitumour efficacy for advanced hepatocellular carcinoma.

BACKGROUND: CD133 is considered a marker for cancer stem cells (CSCs) in several types of tumours, including hepatocellular carcinoma (HCC). Chimeric antigen receptor-specific T (CAR-T) cells targeting CD133-positive CSCs have emerged as a tool for the clinical treatment of HCC, but immunogenicity, the high cost of clinical-grade recombinant viral vectors and potential insertional mutagenesis limit their clinical application. METHODS: CD133-specific CAR-T cells secreting PD-1 blocking scFv (CD133 CAR-T and PD-1 s cells) were constructed using a sleeping beauty transposon system from minicircle technology, and the antitumour efficacy of CD133 CAR-T and PD-1 s cells was analysed in vitro and in vivo. RESULTS: A univariate analysis showed that CD133 expression in male patients at the late stage (II and III) was significantly associated with worse progression-free survival (PFS) (P = 0.0057) and overall survival (OS) (P = 0.015), and a multivariate analysis showed a trend toward worse OS (P = 0.041). Male patients with advanced HCC exhibited an approximately 20-fold higher PD-L1 combined positive score (CPS) compared with those with HCC at an early stage. We successfully generated CD133 CAR-T and PD-1 s cells that could secrete PD-1 blocking scFv based on a sleeping beauty system involving minicircle vectors. CD133 CAR-T and PD-1 s cells exhibited significant antitumour activity against HCC in vitro and in xenograft mouse models. Thus, CD133 CAR-T and PD-1 s cells may be a therapeutically tractable strategy for targeting CD133-positive CSCs in male patients with advanced HCC. CONCLUSIONS: Our study provides a nonviral strategy for constructing CAR-T cells that could also secrete checkpoint blockade inhibitors based on a Sleeping Beauty system from minicircle vectors and revealed a potential benefit of this strategy for male patients with advanced HCC and high CD133 expression (median immunohistochemistry score > 2.284).

BMP9-induced vascular normalisation improves the efficacy of immunotherapy against hepatitis B virus-associated hepatocellular carcinoma.

BACKGROUND: In the past decade, the field of tumour immunotherapy has made a great progress. However, the efficacy of immune checkpoint blocking (ICB) in the treatment of hepatocellular carcinoma (HCC) remains limited. Cytotoxic lymphocyte trafficking into tumours is critical for the success of ICB. Therefore, additional strategies that increase cytotoxic lymphocyte trafficking into tumours are urgently needed to improve patient immune responses. METHODS: Paired adjacent tissue and cancerous lesions with HBV-associated HCC were subjected to RNA-seq analysis. Bone morphogenetic protein (BMP9), which reflects vessel normalisation, was identified through Cytoscape software, clinical specimens and Gene Expression Omnibus (GEO) datasets for HCC. The functional effects and mechanism of BMP9 on the tumour vasculature were evaluated in cells and animals. An ultrasound-targeted microbubble destruction (UTMD)-mediated BMP9 delivery strategy was used to normalise the vasculature and evaluate therapeutic efficacy mediated by cytotoxic lymphocytes (NK cells) in combination with a PD-L1 antibody in human cancer xenografts of immune-deficient mice. RESULTS: We discovered that hepatitis B virus (HBV) infection-induced downregulation of BMP9 expression correlated with a poor prognosis and pathological vascular abnormalities in patients with HCC. BMP9 overexpression in HBV-infected HCC cells promoted intra-tumoural cytotoxic lymphocyte infiltration via vascular normalisation by inhibiting the Rho-ROCK-myosin light chain (MLC) signalling cascade, resulting in enhanced efficacy of immunotherapy. Furthermore, UTMD-mediated BMP9 delivery restored the anti-tumour function of cytotoxic lymphocytes (NK cells) and showed therapeutic efficacy in combination with a PD-L1 antibody in human cancer xenografts of immune-deficient mice. CONCLUSIONS: HBV-induced BMP9 downregulation causes vascular abnormalities that inhibit intra-tumoural cytotoxic lymphocyte infiltration, providing a rationale for developing and combining immunotherapy with BMP9-based therapy to treat HBV-associated HCC.

Alarmin IL-33 orchestrates antitumoral T cell responses to enhance sensitivity to 5-fluorouracil in colorectal cancer.

Rationale: Resistance to 5-fluorouracil (5-FU) chemotherapy remains the main barrier to effective clinical outcomes for patients with colorectal cancer (CRC). A better understanding of the detailed mechanisms underlying 5-FU resistance is needed to increase survival. Interleukin (IL)-33 is a newly discovered alarmin-like molecule that exerts pro- and anti-tumorigenic effects in various cancers. However, the precise role of IL-33 in CRC progression, as well as in the development of 5-FU resistance, remains unclear. Methods: High-quality RNA-sequencing analyses were performed on matched samples from patients with 5-FU-sensitive and 5-FU-resistant CRC. The clinical and biological significance of IL-33, including its effects on both T cells and tumor cells, as well as its relationship with 5-FU chemotherapeutic activity were examined in ex vivo, in vitro and in vivo models of CRC. The molecular mechanisms underlying these processes were explored. Results: IL-33 expressed by tumor cells was a dominant mediator of antitumoral immunity in 5-FU-sensitive patients with CRC. By binding to its ST2 receptor, IL-33 triggered CD4+ (Th1 and Th2) and CD8+ T cell responses by activating annexin A1 downstream signaling cascades. Mechanistically, IL-33 enhanced the sensitivity of CRC cells to 5-FU only in the presence of T cells, which led to the activation of both tumor cell-intrinsic apoptotic and immune killing-related signals, thereby synergizing with 5-FU to induce apoptosis of CRC cells. Moreover, injured CRC cells released more IL-33 and the T cell chemokines CXCL10 and CXCL13, forming a positive feedback loop to further augment T cell responses. Conclusions: Our results identified a previously unrecognized connection between IL-33 and enhanced sensitivity to 5-FU. IL-33 created an immune-active tumor microenvironment by orchestrating antitumoral T cell responses. Thus, IL-33 is a potential predictive biomarker for 5-FU chemosensitivity and favorable prognosis and has potential as a promising adjuvant immunotherapy to improve the clinical benefits of 5-FU-based therapies in the treatment of CRC.

Adjuvant alternative cytokine-induced killer cell combined with natural killer cell immunotherapy improves the prognosis of post-mastectomy breast cancer.

Breast cancer is one of the most common cancers in women. Triple-negative breast cancer (TNBC) has a significantly worse prognosis due to the lack of endocrine receptors including estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2). In this study, we investigated adjuvant cellular immunotherapy (CIT) in patients with post-mastectomy breast cancer. We enrolled 214 post-mastectomy breast cancer patients, including 107 patients in the control group (who received chemotherapy/radiotherapy/endocrine therapy) and the other 107 patients in the CIT group (who received chemotherapy/radiotherapy/endocrine therapy and subsequent immune cell infusion). Of these 214 patients, 54 had TNBC, including 26 patients in the control group and 28 patients in the CIT group. Survival analysis showed that the overall survival rate of patients treated with cellular immunotherapy was higher than that of patients who were not treated with CIT. Compared to those who received cytokine-induced killer (CIK) cells alone, the patients who received CIK combined with natural killer (NK) cell immunotherapy showed the best overall survival rate. In subgroup analyses, adjuvant CIT significantly improved the overall survival of patients in the TNBC subgroup and the patients who were aged over 50 years. Our study indicates that adjuvant CIK cell combined with NK cell treatment is an effective therapeutic strategy to prolong the survival of post-mastectomy patients, particularly for TNBC patients and those who are aged over 50 years.

OTUD4-mediated GSDME deubiquitination enhances radiosensitivity in nasopharyngeal carcinoma by inducing pyroptosis.

BACKGROUND: Radioresistance is the primary cause of nasopharyngeal carcinoma (NPC) treatment failure. Previous studies have focused on the deficits in cellular apoptosis as a mechanism for radioresistance; however, additional potential death modes involved in modulating radiosensitivity of NPC have not been explored. METHODS: Pyroptosis was assessed by phase-contrast imaging, LDH release assays, live cell imaging, and Western blotting. In vitro and in vivo assays were used to investigate the function of gasdermin E (GSDME) and ovarian tumor family deubiquitinase 4 (OTUD4). NPC tissues were analyzed using Western blotting, immunohistochemistry, and real-time PCR. The molecular mechanism was determined using immunoprecipitation assays and mass spectrometry. RESULTS: Live cell imaging revealed that 40-75% of irradiation-induced dead NPC cells were pyroptotic cells. Furthermore, irradiation-induced pyroptosis is triggered by GSDME, which are cleaved by activated caspase-3 in the intrinsic mitochondrial pathway. Additionally, GSDME was significantly downregulated in radioresistant NPC specimens. Low GSDME expression was a predictor of worse prognosis and conferred NPC radioresistance both in vitro and in vivo. Mechanistically, OTUD4 deubiquitinated and stabilized GSDME, enhancing radiosensitivity of NPC cells by promoting pyroptosis. Clinically, OTUD4 was significantly correlated with GSDME in NPC biopsies, and patients with low expression of both OTUD4 and GSDME suffered the worst radiotherapy response and survival. CONCLUSIONS: GSDME-dependent pyroptosis is a critical determinant of radiosensitivity in NPC, and is modulated by OTUD4 via deubiquitinating and stabilizing GSDME. These findings reveal a promising novel direction to investigate radioresistance and suggest potential therapeutic targets for sensitizing NPC to radiotherapy.

SPC25 promotes proliferation and stemness of hepatocellular carcinoma cells via the DNA-PK/AKT/Notch1 signaling pathway.

The imbalance of kinetochore-microtubule attachment during cell mitosis is a response to the initiation and progression of human cancers. Spindle component 25 (SPC25) is indispensable for spindle apparatus organization and chromosome segregation. SPC25 plays an important role in the development of malignant tumors, but its role in hepatocellular carcinoma (HCC) is yet to be determined. In this study, we aimed to preliminarily investigate the role of SPC25 in HCC progression and the molecular mechanisms underlying the process. We identified SPC25 as a clinically notable molecule significantly correlated with the grade of malignancy and poor survival in both The Cancer Genome Atlas (TCGA) cohort and the HCC patient cohort from our center. Mechanistically, SPC25 promoted the incidence of DNA damage and activated the DNA-PK/Akt/Notch1 signaling cascade in HCC cells; the NICD/ RBP-Jκ complex directly targeted SOX2 and NANOG in a transcriptional manner to regulate the proliferation and self-renewal of HCC cells. Our study suggests that HCC-intrinsic SPC25/DNA-PK/Akt/Notch1 signaling is an important mechanism to promote carcinogenesis by regulating the proliferation and stemness program, which provides possible biomarkers for predicting HCC progression and poor survival, as well as potential therapeutic targets for HCC patients.

CircITGB6 promotes ovarian cancer cisplatin resistance by resetting tumor-associated macrophage polarization toward the M2 phenotype.

BACKGROUND: Platinum resistance is a major challenge in the clinical treatment of advanced ovarian cancer (OC). Accumulating evidence shows that the tumor-promotive M2 macrophage is linked to the limiting chemotherapy efficacy of multiple malignancies including OC. Circular RNAs (circRNAs) are a novel class of non-coding RNAs which function as the critical regulator in biological process of cancer. However, their impact on macrophage polarization and chemoresistance of OC remain unclear. METHODS: Platinum-resistant circRNAs were screened using circRNA deep sequencing and validated using in situ hybridization in OC tissues with or without platinum resistance. The role of circITGB6 in inducing cisplatin (CDDP) resistance was evaluated by clone formation, immunofluorescence and annexin V assays in vitro, and by intraperitoneal tumor model in vivo. The mechanism underlying circITGB6-mediated tumor-associated macrophage (TAM) polarization into M2 phenotype was investigated using RNA pull-down, luciferase reporter, electrophoretic mobility shift, RNA binding protein immunoprecipitation (RIP), ELISA and immunofluorescence assays. RESULTS: We identified that a novel circRNA, circITGB6, robustly elevated in tumor tissues and serums from patients with OC with platinum resistance, was correlated with poor prognosis. circITGB6 overexpression promoted an M2 macrophage-dependent CDDP resistance in both vivo and vitro. Mechanistic research determined that circITGB6 directly interacted with IGF2BP2 and FGF9 mRNA to form a circITGB6/IGF2BP2/FGF9 RNA-protein ternary complex in the cytoplasm, thereby stabilizing FGF9 mRNA and inducing polarization of TAMs toward M2 phenotype. Importantly, blocking M2 macrophage polarization with an antisense oligonucleotide targeting circITGB6 markedly reversed the circITGB6-induced CDDP resistance of OC in vivo. CONCLUSIONS: This study reveals a novel mechanism for platinum resistance in OC and demonstrates that circITGB6 may serve as a potential prognostic marker and a therapeutic target for patients with OC.

CMTM6 inhibits tumor growth and reverses chemoresistance by preventing ubiquitination of p21 in hepatocellular carcinoma.

Hepatocellular carcinoma is one of the most common malignancies and has a poor prognosis. The ubiquitin-proteasome pathway is required for the degradation of most short-lived proteins. CMTM6 has been implicated in the progression of various tumors, but its biological function and the underlying molecular mechanisms in HCC are still unknown. In this study, we found that the expression of CMTM6 was significantly reduced in HCC and predicted better prognosis of HCC patients. Through in vitro and in vivo experiments, CMTM6 was shown to inhibit the proliferation of HCC cells by blocking the G1/S phase transition. Mechanistically, CMTM6 interacted with p21 and prevented its ubiquitination mediated by SCFSKP2, CRL4CDT2 and APC/CCDC20 in a cell-cycle-independent manner. As a result, CMTM6 stabilized p21 protein, leading to the inactivation of pRB/E2F pathway. Additionally, CMTM6 sensitized HCC cells to doxorubicin and cisplatin, positively correlated with better clinical outcomes of the transarterial chemoembolization (TACE) treatment for postoperative recurrence. Taken together, our study reports a novel mechanism by which p21 can be stabilized by CMTM6 and pinpoints a crucial role of the CMTM6-p21 axis in suppressing the progression of HCC and sensitizing patients with postoperative recurrence to TACE treatment.

Phase I study of pegylated liposomal doxorubicin and cisplatin in patients with advanced osteosarcoma.

PURPOSE: The repeated use of doxorubicin is limited due to dose-limiting cardiac toxicity. Pegylated liposomal doxorubicin (PEG-LD, Duomeisu) has a reduced cardiac toxicity. This phase I study aimed to investigate the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of the PEG-LD and cisplatin combination in patients with metastatic and recurrent osteosarcoma. METHODS: Patients were given PEG-LD at a dose of 40, 50, or 60 mg/m2 on day 1 of each 21-day cycle, according to a 3 + 3 approach for dose escalation. Cisplatin was administered as a fixed dose of 100 mg/m2 for every cycle. Toxicities and tumor response were observed. RESULTS: A total of 15 patients were enrolled in this trial, and nine of the patients had received prior doxorubicin. The MTD of PEG-LD was reached at 50 mg/m2 in this regimen, with neutropenic fever and stomatitis as DTLs. The main adverse event (AE) was myelosuppression. The most common non-hematological AEs were vomiting, hypoproteinemia, stomatitis and transient sinus arrhythmia. Grade 3-4 toxicity was neutropenia, leukopenia, thrombocytopenia, anemia and stomatitis in the whole cohort. All the AEs were relieved after symptomatic and supportive treatment. Totally, the overall response rate was 13.3% and disease control rate was 66.7%. For the six patients who have not received prior doxorubicin, one partial response and five stable diseases were observed. CONCLUSION: We provide the data showing that PEG-LD 50 mg/m2 combined with cisplatin 100 mg/m2 demonstrated an acceptable safety profile and promising clinical activity in advanced osteosarcoma, which merits further evaluation in phase II studies. TRIAL REGISTRATION: ChiCTR1900021550.